Following the work done in PLANET-5114 & PLANET-5104, we decided to use only dashes in CSS variable names (as opposed to a mix of dashes and underscores). However some of the previously existing variables do not follow this rule, so now we need to update them!

Tasks

• Find all previously existing CSS variables (for example 'footer_links_color') and update their names to use only dashes (most of them are used for campaigns and need to be updated in several places)
• Check child themes, to test if these variables are being used already